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Method for an integrated single photo-mask for dual and multiple exposure lithography

IP.com Disclosure Number: IPCOM000009975D
Publication Date: 2002-Oct-02
Document File: 4 page(s) / 63K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for an integrated single photo-mask for dual and multiple exposure lithography. Benefits include improved throughput and improved performance.

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Method for an integrated single photo-mask for dual and multiple exposure lithography

Disclosed is a method for an integrated single photo-mask for dual and multiple exposure lithography. Benefits include improved throughput and improved performance.

Background

� � � � � Multiple exposure lithography is expensive in terms of cost, throughput time, and overlay registration accuracy in the photo-mask and silicon wafer processes.

� � � � � Conventional technology relies on the fabrication of separate photo-masks for each exposure required in the multiple exposure lithographic technique. For example, alternating phase shift mask technology has two separate masks for poly-silicon gate patterning, phase mask and trim mask. The total cost of poly-gate patterning increases due to fabricating two masks and the rework rate that results from the tight registration requirement between the two masks. By juxtaposing all or some of the separate patterns for multiple exposures onto one mask, the manufacturability issues of cost, throughput time, and registration are improved.

        � � � � � Several techniques can be implemented to minimize the effects of interaction and coupling between the integrated mask patterns and mask structures. The pattern files can be resized. Existing correction patterns can be modified. Additional patterns or substructures designed to compensate total mask process bias and/or coupling effects can be introduced. For example, the ebeam fogging ring for the chrome-level critical dimension (CD) uniformity correction can be modified to compensate the total mask process bias for the integrated mask (see Figure 1).

� � � � � Two masks used for double exposures are the dark-field phase mask and the bright-field trim mask. The ebeam fogging compensation ring is a layout with four-sided large peripheral patterns around the phase mask to improve CD uniformity.

General description

        � � � � � The disclosed method uses the integration of dual or multiple photo-masks for double or multiple exposure lithography into a single photo-mask for resolution enhancement techniques. The integrated mask for multiple exposure lithography can incorporate masks of various types, including:

•        � � � � Chrome-on-glass binary mask

•        � � � � Embedded/attenuated phase shift mask

•        � � � � Alternating phase shift mask

•        � � � � Active optical proximity correction mask

        � � � � � The alternating phase shift mask (altPSM) includes:

•        � � � � Exposed phase edge

•        � � � � Hidden phase edge

•        � � � � Undercut chrome

•        � � � � Sidewall chrome

        � � � � � The process-compatibility issue of integrating diverse mask structures or types on a single plate is resolved by introducing additional mask processing, modifying the existing process, and correcting the lithography or design.

        � � � � � The key element of the method includes a single photo-mask approach for multiple exposure lithography by accommodating dissimilar mask architectures.

Advantages

        � � � � � The disclo...